WW2 bomb craters are a home to rare and vulnerable animals

Some bombs can help create life. A rich mix of rare saline water species have been found thriving in ponds formed in second world war bomb craters in Hungary.

As the number of natural inland ponds dramatically drops throughout Europe due to agricultural land drainage and urbanisation, this discovery backs the case for the inclusion of human-made habitats into conservation initiatives.

“These ‘wartime scars’ might be unnatural, but still can be regarded as valuable bioreserves – just like sunken warships or submarines scattered in the ocean that turned into coral reefs giving refugee to many species,” says Csaba Vad of aquatic ecosystem research centre WasserCluster Lunz in Austria, who led the research.

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A series of miscalculated aerial bombings aimed at a local airport helped to create more than a hundred ponds near the village of Apaj in central Hungary. Similar bomb ponds exist worldwide as a result of war and military training.

The bombs in Hungary happened to fall on a type of habitat known as sodic meadows, which give rise to saline habitats when covered in water.

Naturally occurring inland saline ponds, called soda pans, are unique to this region of Europe. They form part of wider wetlands that harbour a high number of rare and endemic species — but they have been disappearing.

Salt-loving species

The researchers sampled various parts of 54 of these bomb crater ponds to assess the number and type of species living in them. In all, they identified 274 species, including water beetles and turtles, with most of them being salt loving, and several rare and near-vulnerable species.

Some peculiarities turned up: a rare algae (Halamphora dominici) that, apart from central Europe, is only found in Chilean salt lakes, and an also endemic fairy shrimp (Eubranchipus grubii) that has only been recorded twice in the last 25 years in Hungary.

The ponds host hundreds of species

Zsófia Horváth

“These are very understudied habitats. Even though there are many bomb craters in the old war zones of Europe like England or Belgium,” says Vad.

When the team compared life in the bomb crater ponds with their natural counterparts – the soda pans and lakes only present in the Pannonian basin of central Europe – they discovered that the biodiversity is comparable.

Artificial microhabitats

“These craters could serve as excellent scientific models for soda water habitat research, and could have significance for certain species as microhabitats,” says Orsolya Mile of Kiskunsági National Park.

But we shouldn’t overstate their conservation importance, she says: larger, more complex natural soda lakes in the same area have much greater biodiversity.

Vad agrees the craters might be more of a secondary habitat than something to replace the natural pans. Some bomb craters in other parts of Hungary, considered to be unsightly reminders of the war, have already been filled in as part of work to restore grassland.

But as 80 per cent of natural soda pans in Kiskunsági National Park have already disappeared, the crater ponds could still worth protecting, especially as a network connecting natural habitats, says Vad.